Patents by Inventor Eiji Maeno

Eiji Maeno has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20210131532
    Abstract: A chain tensioner is formed with internal threads each including a push-in-side flank, a protruding-side flank , and a thread top face. The push-in-side flank has a flank angle larger than the flank angle of the protruding-side flank. The push-in-side flank and the protruding-side flank are rolled surfaces formed by rolling, and have a surface roughness smaller than Ra 1.0 ?m. Each internal thread further includes, at its position at which the protruding-side flank intersects with the thread top face, a chamfer configured to receive a bulge moving from the protruding-side flank during rolling.
    Type: Application
    Filed: January 11, 2018
    Publication date: May 6, 2021
    Applicant: NTN CORPORATION
    Inventors: Kouichi ONIMARU, Eiji MAENO
  • Patent number: 9677649
    Abstract: A hydraulic auto-tensioner includes a plunger fitted to a bottom end portion of a rod so as to be slidable along a radially inner surface of a valve sleeve and a radially outer surface of the rod. The plunger has a bottom plate formed with a valve hole. A first leakage gap is defined between sliding surfaces of the plunger and the valve sleeve, and a second leakage gap of which the flow resistance is lower is defined between sliding surfaces of the plunger and the rod such that while the engine is running normally, oil in a pressure chamber leaks into a reservoir chamber through the second leakage gap, and when starting the engine by actuating a starter/generator, the plunger rises until the valve hole is closed so that oil in the pressure chamber leaks into the reservoir chamber through the first leakage gap.
    Type: Grant
    Filed: September 16, 2014
    Date of Patent: June 13, 2017
    Assignee: NTN CORPORATION
    Inventors: Satoshi Kitano, Tadahisa Tanaka, Eiji Maeno
  • Publication number: 20160230854
    Abstract: A hydraulic auto-tensioner includes a plunger fitted to a bottom end portion of a rod so as to be slidable along a radially inner surface of a valve sleeve and a radially outer surface of the rod. The plunger has a bottom plate formed with a valve hole. A first leakage gap is defined between sliding surfaces of the plunger and the valve sleeve, and a second leakage gap of which the flow resistance is lower is defined between sliding surfaces of the plunger and the rod such that while the engine is running normally, oil in a pressure chamber leaks into a reservoir chamber through the second leakage gap, and when starting the engine by actuating a starter/generator, the plunger rises until the valve hole is closed so that oil in the pressure chamber leaks into the reservoir chamber through the first leakage gap.
    Type: Application
    Filed: September 16, 2014
    Publication date: August 11, 2016
    Inventors: Satoshi KITANO, Tadahisa TANAKA, Eiji MAENO
  • Patent number: 8684122
    Abstract: A center motor power-assisted bicycle includes an internal transmission and has a regenerative function. A transmission comprises, in a drive wheel hub, a planetary gear, a one-way clutch for reverse input, a clutch switching device, and, a sun gear and transmits driving force from a sprocket to the drive wheel. A transmission control mechanism selectively rotationally fixes the sun gear to the axle to change speed when driving force is applied. The clutch is disposed between the sun gear and the axle, and selectively rotationally fixes the sun gear to the axle by the operation of the clutch switching device when reverse input is applied. While the bicycle is driven, the clutch switching device moves the clutch to the rotatable state, to transmit driving force. While the bicycle is traveling without being driven, the clutch is locked, so that reverse input is transmitted to the sprocket.
    Type: Grant
    Filed: April 27, 2010
    Date of Patent: April 1, 2014
    Assignee: NTN Corporation
    Inventors: Eiji Maeno, Kiyohiro Ito
  • Publication number: 20120227695
    Abstract: A lash adjuster is provided which can be easily assembled and mounted in an arm type valve mounted and in an engine. The valve lifter includes an arm (3) pivotable about a rocker shaft (2), and a lash adjuster (20) mounted in a fitting hole (12) formed in the arm (3) at one end thereof for eliminating a valve clearance. The lash adjuster (20) includes a cylindrical body (21), an adjusting screw (23) held in threaded engagement with an internal thread formed on the inner periphery of the body (21), and a torsion coil spring (31) for applying a rotational moment to the adjusting screw (23) that tends to move the adjusting screw (23) downwardly. With the adjusting screw (23) in threaded engagement with the internal thread (22) of the body (21), the adjusting screw (23) is screwed into the body (21) until the adjusting screw (23) is retracted into the body (21).
    Type: Application
    Filed: December 14, 2010
    Publication date: September 13, 2012
    Inventors: Masashi Bokura, Eiji Maeno
  • Patent number: 8181615
    Abstract: The object is to provide a lash adjuster that can be easily and repeatedly mounted on a swing arm type valve gear, having an adjusting screw that can be repeatedly held in a pushed-in state with a general-purpose turning tool such as a wrench. A serrated internal thread 24 is formed on the inner circumferential face of a cylindrical body 21 having closed bottom end, and a serrated external thread 26 formed on the outer circumferential face of an adjusting screw 25 engages with the internal thread 24. A return spring 27 is mounted in the body to bias the adjusting screw 27 in the protruding direction. A friction member 31 is provided between the bottom faces of the adjusting screw 25 and the body 21. A spherical pivot portion 32 is formed on the top of the adjusting screw 25, and an engaging hole 33 is formed in the top end of the pivot portion 32.
    Type: Grant
    Filed: May 13, 2008
    Date of Patent: May 22, 2012
    Assignee: NTN Corporation
    Inventor: Eiji Maeno
  • Publication number: 20120097467
    Abstract: A power-assisted bicycle of the center motor type is proposed which includes an internally mounted transmission and has a regenerative function with the least complexity of the structure. The bicycle includes a transmission (5) comprising a planetary gear, a one-way clutch (2) for reverse input, and a clutch switching device (9), which are all mounted in a hub (1) of the drive wheel. The transmission (3) includes at least one sun gear and transmits driving force from a sprocket (7) to the drive wheel. The bicycle further includes a transmission control mechanism (10) for selectively rotationally fixing the sun gear to the axle (5) to change speed when driving force is applied. The one-way clutch (2) for reverse input is disposed between the at least one sun gear (5a) and the axle (11), and selectively rotationally fix the sun gear to the axle (11) by the operation of the clutch switching device (9) when reverse input is applied.
    Type: Application
    Filed: April 27, 2010
    Publication date: April 26, 2012
    Inventors: Eiji Maeno, Kiyohiro Ito
  • Patent number: 8136493
    Abstract: A lash adjuster is provided which includes a cylindrical housing having an open top and formed with an internal thread on an inner periphery thereof, a screw rod having an external thread formed on an outer periphery thereof and in threaded engagement with the internal thread, and a spring biasing the screw rod outwardly of the housing. Each of the internal thread and the external thread having a pressure flank configured to receive pressure when a force that tends to push the screw rod into the housing acts on the screw rod, and a clearance flank having a smaller flank angle than the pressure flank. The screw rod has an end protruding from the housing and configured to support an arm of a valve operating mechanism so as to be pivotable about this end. Oil film expelling grooves are formed in the pressure flank of the external thread, using a tap having a thread that extends so as to cross the internal thread.
    Type: Grant
    Filed: April 10, 2008
    Date of Patent: March 20, 2012
    Assignee: NTN Corporation
    Inventors: Katsuhisa Yamaguchi, Hiroshi Bunko, Eiji Maeno
  • Publication number: 20110036314
    Abstract: The object is to prevent rotation of the case when a load is applied to the adjusting screw that tends to push in the adjusting screw.
    Type: Application
    Filed: March 16, 2009
    Publication date: February 17, 2011
    Inventors: Makoto Yasui, Eiji Maeno, Katsuhisa Yamaguchi
  • Publication number: 20110017161
    Abstract: A lash adjuster is provided of which an adjusting screw can be repeatedly fixed in position. The lash adjuster includes a nut member 14 having an internal thread 15 on an inner periphery thereof, an adjusting screw 17 having a external thread 16 on the outer periphery thereof which is in threaded engagement with the internal thread 15, and a return spring 19 biasing the adjusting screw 17 in the direction to protrude from the nut member 14, wherein the lash adjuster further includes an initial setting member 25 detachably disposed between the adjusting screw 17 and the nut member 14, and wherein the adjusting screw 17 is fixed to the nut member 14 due to frictional forces between the initial setting member 25 and the adjusting screw 17 and between the initial setting member 25 and the nut member 14.
    Type: Application
    Filed: March 18, 2009
    Publication date: January 27, 2011
    Inventors: Makoto Yasui, Eiji Maeno, Katsuhisa Yamaguchi
  • Publication number: 20110005484
    Abstract: A lash adjuster is provided of which the adjusting screw can be repeatedly and easily brought into the initial set position. In a lash adjuster including a nut member 14 having an internal thread 20 on the inner periphery thereof, an adjusting screw 15 having an external thread 19 on the outer periphery thereof that is in threaded engagement with the internal thread 20, and a return spring 17 biasing the adjusting screw 15 in the direction to protrude from the nut member 14, a washer 18 is provided which is axially deformed and produces frictional resistance to rotation that serves to prevent rotation of the adjusting screw 15 by its elastic restoring force when the adjusting screw 15 is threaded into the nut member 14.
    Type: Application
    Filed: September 19, 2008
    Publication date: January 13, 2011
    Inventors: Makoto Yasui, Eiji Maeno, Katsuhisa Yamaguchi
  • Publication number: 20100288219
    Abstract: A lash adjuster is provided of which the return spring is never compressed excessively when the adjusting screw is pushed into the nut member, and of which the external thread on the outer periphery of the adjusting screw can be formed easily by rolling. The lash adjuster 1 includes a nut member 12 having an internal thread 13, an adjusting screw 15 having an external thread 14 on its outer periphery which is in threaded engagement with the internal thread 13, and a return spring 17 biasing the adjusting screw 15 in the direction to protrude from the nut member 12. The adjusting screw 15 pivotally supports an arm 7 of a valve gear at its end protruding from the nut member 12. The adjusting screw 15 has at its portion protruding from the nut member 12 a stopper portion 23 having a larger diameter than the inner diameter of the nut member 12.
    Type: Application
    Filed: January 16, 2009
    Publication date: November 18, 2010
    Inventors: Makoto Yasui, Katsuhisa Yamaguchi, Eiji Maeno
  • Publication number: 20100275865
    Abstract: A lash adjuster includes a nut member inserted in a receiving hole formed in the top surface of a cylinder head, an adjusting screw having an external thread on its outer periphery which is in threaded engagement with an internal thread on the inner periphery of the nut member, and a return spring biasing the adjusting screw. The adjusting screw has an end protruding from the nut member and pivotally supporting an arm of a valve gear. The adjusting screw is a solid member. A spring seat is disposed between the adjusting screw and the return spring and kept in point contact with the end of the adjusting screw inserted in the nut member. The spring seat is axially slidably fitted in the inner periphery of the nut member, thereby keeping the adjusting screw and the spring seat coaxial with each other.
    Type: Application
    Filed: January 26, 2009
    Publication date: November 4, 2010
    Inventors: Makoto Yasui, Katsuhisa Yamaguchi, Eiji Maeno
  • Publication number: 20100263614
    Abstract: A lash adjuster is provided in which the friction coefficient between the pressure flanks is less likely to decrease over a long time use. The lash adjuster 1 includes a nut member 10 having an internal thread 17 on its inner periphery, an adjusting screw 11 having an external thread 18 on its outer periphery which is in threaded engagement with the internal thread 17, and a return spring 12 biasing the adjusting screw 11 in a direction to protrude from the nut member 10, the external thread 18 and the internal thread 17 having pressure flanks 19 and 21, respectively, for receiving an axial load that tends to push the adjusting screw 11 into the nut member 10, wherein a satin finished surface is formed on the pressure flank 19 of the external thread 18, and the satin finished surface has a higher surface hardness than the pressure flank 21 of the internal thread 17.
    Type: Application
    Filed: December 19, 2008
    Publication date: October 21, 2010
    Inventors: Makoto Yasui, Eiji Maeno, Katsuhisa Yamaguchi
  • Publication number: 20100263613
    Abstract: The object is to prevent the adjusting screw from being pushed in while rotating when a load is applied to the adjusting screw that tends to push in the adjusting screw. In a lash adjuster comprising a cylindrical housing 12 inserted in a receiving hole 11 formed in the top surface of a cylinder head 2 and having an internal thread 13 on the inner periphery thereof, an adjusting screw 15 having an external thread 14 on the outer periphery thereof and in threaded engagement with the internal thread 13 on the housing 12, and a return spring 17 biasing the adjusting screw 15 in a direction to protrude upwardly from the housing 12, the adjusting screw 15 having a protruding end 19 protruding from the housing 12 and supporting an arm 7, the surface of the protruding end 19 of the adjusting screw 15 is made of a material that does not react with oil additives of oil containing organic molybdenum.
    Type: Application
    Filed: December 2, 2008
    Publication date: October 21, 2010
    Inventors: Makoto Yasui, Eiji Maeno, Katsuhisa Yamaguchi
  • Publication number: 20100126453
    Abstract: The object is to provide a lash adjuster that can be easily and repeatedly mounted on a swing arm type valve gear, having an adjusting screw that can be repeatedly held in a pushed-in state with a general-purpose turning tool such as a wrench. A serrated internal thread 24 is formed on the inner circumferential face of a cylindrical body 21 having closed bottom end, and a serrated external thread 26 formed on the outer circumferential face of an adjusting screw 25 engages with the internal thread 24. A return spring 27 is mounted in the body to bias the adjusting screw 27 in the protruding direction. A friction member 31 is provided between the bottom faces of the adjusting screw 25 and the body 21. A spherical pivot portion 32 is formed on the top of the adjusting screw 25, and an engaging hole 33 is formed in the top end of the pivot portion 32.
    Type: Application
    Filed: May 13, 2008
    Publication date: May 27, 2010
    Inventor: Eiji Maeno
  • Publication number: 20100071648
    Abstract: A lash adjuster is provided which includes a cylindrical housing having an open top and formed with an internal thread on an inner periphery thereof, a screw rod having an external thread formed on an outer periphery thereof and in threaded engagement with the internal thread, and a spring biasing the screw rod outwardly of the housing. Each of the internal thread and the external thread having a pressure flank configured to receive pressure when a force that tends to push the screw rod into the housing acts on the screw rod, and a clearance flank having a smaller flank angle than the pressure flan. The screw rod has an end protruding from the housing and configured to support an arm of a valve operating mechanism so as to be pivotable about this end. Oil film expelling grooves are formed in the pressure flank of the external thread, using a tap having a thread that extends so as to cross the internal thread.
    Type: Application
    Filed: April 10, 2008
    Publication date: March 25, 2010
    Inventors: Katsuhisa Yamaguchi, Hiroshi Bunko, Eiji Maeno
  • Patent number: 7571632
    Abstract: This invention provides a chain tensioner that is compact, excellent in operation, easy to maintain and handle and low in manufacturing cost. This chain tensioner has a tubular housing 1 having a bottom, a plunger 3 installed in the inner periphery 1a of the housing so as to smoothly slide inside the housing, a return spring 5 providing the plunger 3 with a force pushing outward, a plurality of latching grooves 33a-33d formed on the outer periphery of the plunger 3, a resister ring 7 capable of locking in the latching grooves, and a check valve 6 that is mounted on the bottom of the housing inner periphery 1a, provides the housing inner periphery 1a with operating oil and prevents its reverse flow. The range of backward movement of the plunger 3 is limited by mating the resister ring 7 locked in the latching grooves 33a-33d with a first stopper 21 formed on the housing inner periphery 1a.
    Type: Grant
    Filed: May 2, 2007
    Date of Patent: August 11, 2009
    Assignee: NTN Corporation
    Inventors: Ken Yamamoto, Eiji Maeno
  • Publication number: 20070213152
    Abstract: This invention provides a chain tensioner that is compact, excellent in operation, easy to maintain and handle and low in manufacturing cost. This chain tensioner has a tubular housing 1 having a bottom, a plunger 3 installed in the inner periphery 1a of the housing so as to smoothly slide inside the housing, a return spring 5 providing the plunger 3 with a force pushing outward, a plurality of latching grooves 33a-33d formed on the outer periphery of the plunger 3, a resister ring 7 capable of locking in the latching grooves, and a check valve 6 that is mounted on the bottom of the housing inner periphery 1a, provides the housing inner periphery 1a with operating oil and prevents its reverse flow. The range of backward movement of the plunger 3 is limited by mating the resister ring 7 locked in the latching grooves 33a-33d with a first stopper 21 formed on the housing inner periphery 1a.
    Type: Application
    Filed: May 2, 2007
    Publication date: September 13, 2007
    Inventors: Ken Yamamoto, Eiji Maeno
  • Patent number: 7189174
    Abstract: This invention provides a chain tensioner that is compact, excellent in operation, easy to maintain and handle and low in manufacturing cost. This chain tensioner has a tubular housing 1 having a bottom, a plunger 3 installed in the inner periphery 1a of the housing so as to smoothly slide inside the housing, a return spring 5 providing the plunger 3 with a force pushing outward, a plurality of latching grooves 33a–33d formed on the outer periphery of the plunger 3, a resister ring 7 capable of locking in the latching grooves, and a check valve 6 that is mounted on the bottom of the housing inner periphery 1a, provides the housing inner periphery 1a with operating oil and prevents its reverse flow. The range of backward movement of the plunger 3 is limited by mating the resister ring 7 locked in the latching grooves 33a–33d with a first stopper 21 formed on the housing inner periphery 1a.
    Type: Grant
    Filed: December 10, 2001
    Date of Patent: March 13, 2007
    Assignee: NTN Corporation
    Inventors: Ken Yamamoto, Eiji Maeno